Most disc drives use fly-height control to maintain a head to media separation at a controlled distance during data write operations. Preamplifier heater circuitry can assist fly-height control by delivering a programmable constant power to a resistive heater element on a slider to generate heat to effect protrusion in the slider element.
Currently, heater driver outputs from a preamplifier are from linear heater drivers as shown in FIG. 3. Such linear heater drivers deliver a continuous direct current (DC) constant Voltage/Power to a resistive heat element depending on a digital-to-analog conversion (DAC) setting in the preamplifier. The linear heat drivers suffer power loss and heat dissipation in the output stage. This can cause excessive power consumption for a device with a heater driver and is particular problematic for battery powered devices with a heater driver.
Therefore, there is a need for an improved device and method for controlling a heat resistive element of a transducer.